Blade attachment



1962 w. s. CASTLE ETAL 3,056,581

BLADE ATTACHMENT Filed Oct. 14. 1959 2 Sheets-Sheet l INVENTORJ ATTORNEY1962 w. s. CASTLE ETAL 3,056,581

BLADE ATTACHMENT Filed Oct. 14, 1959 2 Sheets-Sheet 2 /flfl :2; if ya 11/ 17 7/ OHO QWLJL 6/ 52 INVENTORS ATTORNEY ilit hoe

3,056,581 BLADE ATTACHMENT William S. Castle, Speedway, and John B.Minnich, Indianapolis, Ind, assignors to General Motors Corporation,Detroit, Mich., a corporation of Delaware Filed Oct. 14, 1959, Ser. No.846,426 4 Claims. (Cl. 253-77) This invention relates to a rotorassembly.

More particularly, it is an object of this invention to provide a lowcost fabricated rotor assembly that is easy to assemble and disassemble.

Other objects, features and advantages will become apparent uponreference to the succeeding detailed description and to the drawingsillustrating the preferred embodiments of the invention, wherein,

FIGURE 1 is a front elevational view with parts broken away and insection of one embodiment of the invention,

Figure 2 is an enlarged cross-sectional view taken on a plane indicatedby and viewed in the direction of the arrows 2-2 of FIGURE 1,

FIGURE 3 is a cross-sectional view taken on a plane indicated by andviewed in the direction of arrows 3-3 of FIGURE 2,

FIGURE 4 is an enlarged exploded perspective view of a detail,

FIGURE 5 is a front elevational View with parts broken away and insection of another embodiment of the invention,

FIGURE 6 is an enlarged cross-sectional view taken on a plane indicatedby and viewed in the direction of arrows 66 of FIGURE 5, and

FIGURE 7 is a cross-sectional view taken on a plane indicated and viewedin the direction of arrows 77 of FIGURE 6.

Referring to the drawings and more particularly to FIGURE 1, there isshown therein an arcuate portion 10 of an axial flow type rotor assembly12 incorporating one embodiment of this invention, the assemblyincluding a number of blades 14 adapted to be secured to a wheel 16 andspaced equally circumferentially therearound by a number of spacers 18,the blades, spacers and wheels being secured to each other and to anumber of reinforcing and attaching members 20.

Referring more particularly to the details, each of the blades 14 ispreferably stamped from sheet metal in the shape of an air foil as shownand having a radial slot 22 provided centrally therein at the reducedradially inner end 24 for receiving the wheel or disk 16 therein. Theblades 14 are joined to the wheel 16 by a number of right anglereinforcing bracket members having axially extending leg portions 26secured to the blades by the insertion of rivets 28 or the like throughsuitable holes 30 and 32 provided in each, and circumferentiallyextending leg portions 34 adapted to be secured to the wheel.

Each of the leg portions 34 is stamped to provide a stepped or tongueportion 36 to permit a circumferential interfit between oppositelypositioned adjacent leg portions upon assembly thereof so that both acircumferential and radial stop is provided preventing relative movementbetween the blades and wheel. A minimum clearance is maintained betweenthe interfitted portions to permit growth upon thermal expansion of theparts. The interfitted portions together therefore constitute asubstantially U-shaped reinforcing member between adjacent blades.

Adapted to overlie the adjacent leg portions 34 of the bracket membersand completely span the circumferential space between radially innerportions of the blades are the spacer means 18 equally spacing theblades around the periphery of the wheel and also constituting a bafllepreventing the flow of gas in an axial direction between blades exceptas to be described. Each of the spacer means 18 comprises two radiallyextending sheet metal plates 38 and 40 each of a width equal to thedesired circumferential distance between blades. Plates 38 and 40 areaxially spaced from each other as shown in FIGURE 2 and flanged at theirradially outer portions 42 and 44 for cooperation with a top sheet metalplate portion 46 constituting a blade platform over which the gasespassing between the blades are directed. Leg portions 38 and 40 areadapted to overlie adjacent leg portions 34 of the reinforcing bracketmembers 20 to join them together and to the wheel in a manner to be described to provide a rigid connection therebetween. The spacer leg 38also provides a streamlined unbroken frontal area against which thegases impinge, thus reducing friction losses, etc. The angle at whichthe platform is directed with the axis is that providing the mostefficient angle of flow of the gas passing between blades.

In the assembly of this embodiment of the invention, the axial legportions 32 of the reinforcing members 20 are initially riveted to theblades 14 on both sides thereof as shown in FIG. 3. The slotted end 24of each of the blades is then dropped into position over the wheel 16with the rivet holes 48 provided in the circumferential leg portions 34of the brackets being aligned with the holes 50 provided in the wheel,and the oppositely positioned stepped portions 36 of adjacent bracketsinterfitting as shown in FIGURES 1 and 4 to provide a circumferentialand radial stop therebetween. The spacers 18, which have beenpreassembled by riveting the platform 46 to the leg portions 38 and 40'at 52 and 54, are then positioned in place between the blades and overthe bracket legs 34 and wheel 16, with the rivet holes 58 provided inthe spacer legs aligned with holes 48 and 50 in the brackets and wheel,and the whole assembly is riveted together. The assembly is thus rigidlyconnected together with the spacers completely spanning the gap betweenblades to force the gas passing therebetween to flow over and at theangle of the platform.

FIGURES 5-7 illustrate a different embodiment of the invention whereinthe fabricated assembly includes a plurality of circumferentially spacedsheet metal air foils or blades 60 adapted to cooperate with a rotorconsisting of two annular axially spaced flat sheet metal plates 62 and64. Each of the air foils 60 is formed with a reduced inner radial tangportion 66 recessed or cut back at 68 to form a further reduced section70 of an axial width to fit tightly between the two plates 62 and 64,the point of cut back of the tang as shown in FIGURE 6 thereforeproviding shoulders or steps 72 constituting a stop to radially locatethe blade with respect to the wheel.

As in the FIGS. 1-4 construction, each of the blades is secured to therotor plates by four right angle bracket members 74, two cooperatingwith each other on each side of the blade to together form asubstantially U-shaped member, the brackets having axial leg portions76' riveted to the blades as shown at 78 and 80 in FIGURE 6 andcircumferentially extending leg portions 84 adapted to be secured to theplates.

The spacer means 86 comprise two axially spaced radially extending legportions 88 and 90 flanged at their ends 92 and 94 and riveted at 96 and98 to a top plate to that of FIG. 1, i.e., the axial leg portions 76 ofbracket members 102 and 104 are riveted to the reduced portion 70 of theairfoil tank at 78 and 80, the tang is then dropped into positionbetween the plates until the shoulders 72 rest on the upper edges of theplates and the rivet holes 106 provided in the circumferential legs 84align with holes 107 drilled in the plates, the spacers are thenpositioned against the inside of the brackets with the rivet holes 110therein aligned with holes 106 and 108, and the entire assembly is thenrigidly locked together by riveting of the same as shown.

From the foregoing, it will be seen therefore that this inventionprovides an easily assembled and disassembled fabricated rotor assemblyconstructed of sheet metal to provide an economical assembly.

While the invention has been illustrated in its preferred embodiments inFIGS. l-7, it will be clear to those skilled in the art to which thisinvention pertains that many modifications may be made without departingfrom the scope of the invention.

We claim:

1. A rotor blade assembly comprising a disk, a plurality of bladesadapted to straddle and be secured to said disk at the peripherythereof, spacer means for circumferentially spacing said blades andspanning the gap therebetween, and securing means for securing saidblades, spacer means and said disk rigidly together, said meanscomprising a plurality of substantially right angle reinforcing memberseach having leg portions secured to one of said blades and other legportions secured to said disk, said other portions of adjacent membersbeing interfitted with each other to provide circumferential and radialstops for the movement of said blades relative to said disk.

2. A rotor blade assembly comprising a thin disk, a plurality of bladesadapted to be secured to said disk at the periphery thereof, spacermeans for circumferentially spacing said blades and spanning the gaptherebetween, and securing means for securing said blades, spacer meansand said disk rigidly together, said means comprising a plurality ofsubstantially right angle reinforcing members each having first legportions secured to one of said blades and other leg portions secured tosaid disk, said blades each having a slot therein at one end forstraddling the periphery of said disk therein, adjacent leg portions ofsaid members having a stepped construction permitting a circumferentialinterfit therebetween to circumferentially and radially locate saidblades with respect to said disk.

3. A lightweight fabricated rotor assembly comprising a thin sheet metaldisk, a plurality of slotted airfoil type blades adapted to straddle theouter periphery of said disk and extend laterally therefrom, spacermeans circumferentially spacing said blades, a plurality of bracketmembers securing each of said blades to said disk, and means to connectsaid spacer means to mutually adjacent bracket members and said disk torigidly connect mutually adjacent blades to each other and said disk,adjacent portions of said brackets having radially and circumferentiallyinterlocking parts to align said blades relative to each other and saiddisk.

4. A lightweight fabricated rotor assembly comprising a thin sheet metaldisk, a plurality of slotted airfoil type blades adapted to straddle theouter periphery of said disk and extend laterally therefrom, spacermeans between said blades for circumferentially spacing said blades, aplurality of substantially right angle bracket members securing each ofsaid blades to said disk, and means to connect said spacer means tomutually adjacent bracket members and said disk to rigidly connectmutually adjacent blades to each other and said disk, adjacent portionsof said brackets having radially and circumferentially interlockingparts to align said blades relative to each other and said disk.

References Cited in the file of this patent UNITED STATES PATENTS926,442 Smoot June 29, 1909 2,867,407 Stalker June 2, 1959 FOREIGNPATENTS 163,871 Australia July 5, 1955 718,139 Great Britain Nov. I0,1954

